As for laterite-type bauxite deposits, it is generally believed that they were formed by weathering of aluminum-bearing rocks under modern climate conditions. There is only one subtype of laterite-type bauxite deposits, which is called Zhangpu-type laterite-type bauxite deposits. It only accounts for 1.17% of China's total bauxite reserves. Modern laterite-type bauxite in China is mainly formed in low-latitude areas, such as Fujian, Hainan and some areas in Guangdong. These areas have hot weather, abundant rainfall, and easily weathered basalt, so modern laterite-type bauxite can be formed. As for China's Nansha Islands and Zhongsha Islands, although they are also at low latitudes and have a climate where bauxite is formed, the time for these islands to rise to land is not long, only 10,000 to 30,000 years, and the time to withstand weathering is short, so it is difficult to Formation of bauxite deposits.
Residual bauxite is mostly formed on aluminosilicate and limestone, and this lateritization generally occurs in tropical and subtropical regions. The tropical and subtropical climates alternate between rainy and dry seasons, and the seasons are of equal length. During the rainy season, the rainfall is large (1500 mm to 2500 mm), and there is basically no rainfall in the dry season. The temperature is hot throughout the year, and the temperature difference between day and night is small, which is conducive to the growth of plants and the reproduction of microorganisms. Under such climatic conditions, the organic matter (humus, organic acids, etc.) on the surface is extremely rich, thus accelerating the progress of chemical weathering.
An important natural condition for the formation of bauxite is a hot and rainy humid climate, in turn bauxite can be considered as a sign of ancient humid climate, but it may be related to sediments of which the importance of paleoclimate is not yet known (e.g. related to the groundwater table). ferrous hard soil layers), many scholars have used weathering profiles in which bauxite occupies an appropriate position in the sequence to verify
